New Scientist - Quark Nova Project
... stranger. They may mark the violent birth of a quark star, a cosmic oddity that has only existed so far in the imaginations and equations of a few physicists. If so they would be the strongest hints yet that these celestial creatures exist in the cosmic wild. The implications would be enormous. Thes ...
... stranger. They may mark the violent birth of a quark star, a cosmic oddity that has only existed so far in the imaginations and equations of a few physicists. If so they would be the strongest hints yet that these celestial creatures exist in the cosmic wild. The implications would be enormous. Thes ...
Module code: AA1
... The hypothetical question how the night sky would appear if all stars would possess the same luminosity as the sun or Barnard’s star was analysed with Excel diagrams leading to the conclusion that in case of the sun the night sky would have less bright stars and in case of Barnard’s star with the na ...
... The hypothetical question how the night sky would appear if all stars would possess the same luminosity as the sun or Barnard’s star was analysed with Excel diagrams leading to the conclusion that in case of the sun the night sky would have less bright stars and in case of Barnard’s star with the na ...
Morphological characteristics of OB spectra and environments
... The causes and effects of rotation in massive stellar evolution, involving mixing or transfer of processed material to the surface and enhanced mass loss, are active areas of current research [10, 17, 7]. In particular, enhanced N/C abundance ratios in the atmospheres and winds are a vital diagnosti ...
... The causes and effects of rotation in massive stellar evolution, involving mixing or transfer of processed material to the surface and enhanced mass loss, are active areas of current research [10, 17, 7]. In particular, enhanced N/C abundance ratios in the atmospheres and winds are a vital diagnosti ...
Measuring the Stars pages 813-820
... the winter, because they are on the ether side of the sun. ...
... the winter, because they are on the ether side of the sun. ...
Astronomy HOMEWORK Chapter 15 1. Where in the Galaxy is the
... are too high to be explained by the mass of stars, gas, and dust inside their orbits. In particular, as one goes into the extreme outskirts, orbital speeds continue to climb. Kepler’s third law would require them to go down, if there were not some large mass density in these extreme outskirts. The s ...
... are too high to be explained by the mass of stars, gas, and dust inside their orbits. In particular, as one goes into the extreme outskirts, orbital speeds continue to climb. Kepler’s third law would require them to go down, if there were not some large mass density in these extreme outskirts. The s ...
CURRICULUM COMMITTEE COURSE PROPOSAL FORM
... The discovery of exoplanets is one of the greatest revolutions in modern astronomy. Over eighteen hundred exoplanets have been discovered to date. The universe is teeming with planets - hot Jupiter-like planets skimming the surfaces of their stars, free-floating planets far from any star, super-Eart ...
... The discovery of exoplanets is one of the greatest revolutions in modern astronomy. Over eighteen hundred exoplanets have been discovered to date. The universe is teeming with planets - hot Jupiter-like planets skimming the surfaces of their stars, free-floating planets far from any star, super-Eart ...
White dwarfs from GAIA: The 7th dimension
... • The white dwarf luminosity function of Gaia is a sensitive probe of the averaged star formation rate • Due to their very short main-sequence lifetimes the shape of the SFR can be reconstructed from the luminosity function of massive white dwarfs • To achieve these goals, we need R~5000 spectroscop ...
... • The white dwarf luminosity function of Gaia is a sensitive probe of the averaged star formation rate • Due to their very short main-sequence lifetimes the shape of the SFR can be reconstructed from the luminosity function of massive white dwarfs • To achieve these goals, we need R~5000 spectroscop ...
Feedback - Cambridge University Press
... Supernovae produce high velocity (∼ 2000 km s−1 ) high temperature winds, but observed winds have much higher mass loss rates than those that would be produced by SNe alone. In addition, observed winds have the bulk of their gas in a high density, low T , and relatively low velocity (300 − 1000 km s ...
... Supernovae produce high velocity (∼ 2000 km s−1 ) high temperature winds, but observed winds have much higher mass loss rates than those that would be produced by SNe alone. In addition, observed winds have the bulk of their gas in a high density, low T , and relatively low velocity (300 − 1000 km s ...
hwk06ans
... 0.5Msun : L 0.08 Lsun , T0 roughly 13 million K. 5 Msun : L 390 Lsun , T0 roughly 20 or 21 million K. Thus a ratio of 5000 in luminosity corresponds to a ratio of only 1.6 in T0 . Note: T0 M / R is important but it's also very rough. It depends on assuming homologous interior structure an ...
... 0.5Msun : L 0.08 Lsun , T0 roughly 13 million K. 5 Msun : L 390 Lsun , T0 roughly 20 or 21 million K. Thus a ratio of 5000 in luminosity corresponds to a ratio of only 1.6 in T0 . Note: T0 M / R is important but it's also very rough. It depends on assuming homologous interior structure an ...
PH607lec10
... formation event a few million years ago. The existence of these relatively young (though evolved) stars there was of a surprise to experts, who would have expected the tidal forces from the central black-hole to prevent their formation. They are much too young to have migrated far, but it seems even ...
... formation event a few million years ago. The existence of these relatively young (though evolved) stars there was of a surprise to experts, who would have expected the tidal forces from the central black-hole to prevent their formation. They are much too young to have migrated far, but it seems even ...
Rotation - Indiana University Astronomy
... – Must find stars very near ZAMS since winds in massive stars may cause significant loss of angular momentum on time scales of few times 106 yrs – Masses also uncertain ...
... – Must find stars very near ZAMS since winds in massive stars may cause significant loss of angular momentum on time scales of few times 106 yrs – Masses also uncertain ...
GRAVITATIONAL RADIATION FROM ACCRETING NEUTRON STARS
... longer than assumed by Brady, et al, and this again reduces the parameter space that must be searched. Moreover, the orbital of the star can be taken to be circular, if it is inside the envelope of the companion: eccentricity will rapidly dissipate. Here we make some preliminary estimates of the dif ...
... longer than assumed by Brady, et al, and this again reduces the parameter space that must be searched. Moreover, the orbital of the star can be taken to be circular, if it is inside the envelope of the companion: eccentricity will rapidly dissipate. Here we make some preliminary estimates of the dif ...
Document
... • Molecular Gas Mass as traced by CO emission and the star formation rate in spiral galaxies, LIRGS, ULIRGs and high z molecular galaxies (Early Molecular Galaxies, EMGs) • Dense molecular Gas as traced by HCN emission is a star formation rate indicator. The mass of dense molecular gas is the key to ...
... • Molecular Gas Mass as traced by CO emission and the star formation rate in spiral galaxies, LIRGS, ULIRGs and high z molecular galaxies (Early Molecular Galaxies, EMGs) • Dense molecular Gas as traced by HCN emission is a star formation rate indicator. The mass of dense molecular gas is the key to ...
Multiple Choice, continued Stars, Galaxies, and the Universe
... Today, we know that Copernicus was right: the stars are very far from Earth. In fact, stars are so distant that a new unit of length—the light-year—was created to measure their distance. A light-year is a unit of length equal to the distance that light travels through space in 1 year. Because the sp ...
... Today, we know that Copernicus was right: the stars are very far from Earth. In fact, stars are so distant that a new unit of length—the light-year—was created to measure their distance. A light-year is a unit of length equal to the distance that light travels through space in 1 year. Because the sp ...
The Magnetic Field Profile in Strongly Magnetized Neutron Stars
... Summary and Outlook - we provide the first realistic magnetic-field profile for the EoS of magnetized neutron stars - our profile is obtained from the solution of Einstein's equations and does not violate Maxwell’s equations - our results allow anyone to include a B profile in any neutron star EoS ...
... Summary and Outlook - we provide the first realistic magnetic-field profile for the EoS of magnetized neutron stars - our profile is obtained from the solution of Einstein's equations and does not violate Maxwell’s equations - our results allow anyone to include a B profile in any neutron star EoS ...
Stellar evolution
Stellar evolution is the process by which a star changes during its lifetime. Depending on the mass of the star, this lifetime ranges from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are born from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star.Nuclear fusion powers a star for most of its life. Initially the energy is generated by the fusion of hydrogen atoms at the core of the main-sequence star. Later, as the preponderance of atoms at the core becomes helium, stars like the Sun begin to fuse hydrogen along a spherical shell surrounding the core. This process causes the star to gradually grow in size, passing through the subgiant stage until it reaches the red giant phase. Stars with at least half the mass of the Sun can also begin to generate energy through the fusion of helium at their core, whereas more-massive stars can fuse heavier elements along a series of concentric shells. Once a star like the Sun has exhausted its nuclear fuel, its core collapses into a dense white dwarf and the outer layers are expelled as a planetary nebula. Stars with around ten or more times the mass of the Sun can explode in a supernova as their inert iron cores collapse into an extremely dense neutron star or black hole. Although the universe is not old enough for any of the smallest red dwarfs to have reached the end of their lives, stellar models suggest they will slowly become brighter and hotter before running out of hydrogen fuel and becoming low-mass white dwarfs.Stellar evolution is not studied by observing the life of a single star, as most stellar changes occur too slowly to be detected, even over many centuries. Instead, astrophysicists come to understand how stars evolve by observing numerous stars at various points in their lifetime, and by simulating stellar structure using computer models.In June 2015, astronomers reported evidence for Population III stars in the Cosmos Redshift 7 galaxy at z = 6.60. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.